Milkweed seed oil



Patented Aug. 30, 1949 UNITED STATES OFFICE MILKWEED SEED OIL r N Drawing.

The present invention relates to a process of preparing oil from milkweed seed. Considerable interest has been evoked; of recent years in the milkweed, both as a source of rubber and as a source of vegetable fiber. It has now been discovered that a valuable oil can be recovered from the seed of the milkweed and may be used for edible purposes as well as for preparing protectivecoatings.

The milkweed seed is of the samara type having a thin fin extending around the seed. I have discovered that by removing the fin and by controlling to some extent the moisture content of the seed, it is possible to press out practically all of the oil of the seed. The oil possesses an excellent appearance and'taste, resembling that of first pressing olive oil, and was found to be an excellent salad 011i By] suitable heat or chemical treatment the oil can be bodiedor partially polymerized and as such is applicable for protective coatings.

It is, therefore, an objectof the present invention to provide a process of recovering valuable oil products from milkweed' seed. It is another object of the present invention to provide a process of recovering oil from milkweed seed useful for edible purposes, as well as for protective coatings. It is a further object of the present invention to provide a process'of removing fins from the milkweed seed. i

These and other objectsof the present invention will be readily apparent from the description thereof with particular reference to various examples which are to be understood as illustrative only and in no sense limiting the invention.

The seeds may be prepared for processing as follows: The pods maybe collected from the plants by hand or by a suitable harvesting machine. I have discovered that the simplest way found to recover the seed from the pod has been to pass the entire pod (hull, floss, seed) into a centrifugal type fan or blower, the impeller of which is operating at a peripheral velocity of 5000 ft. or over per minute. The impact of the blades and fan housing on the'pods is suflicient to open the pods, dislodge the floss and detach the seeds. The discharge from the blower is then passed through a cyclone separator in which the seed and hulls are separated from the floss, an accelerated air flotation separation, the floss passing out the upper discharge vent along with the air and the seed and hulls from the bottom. The seed and hulls can be separated by customary screening procedure. This method and the apparatus therefor are the subject of a copcnding application,

Application February 21, 1944, SerialNo. 523,357

teams; (01. 260-4122) 7 During this step of the process, the moisture content is preferably controlled to between and 25 per cent. At lower moisture contents, excessive breakage of floss and seed results, whereas at higher moisture contents, the material may 7 heat in storage.

' tioned above.

I have discovered that it is diflicult, if not impossible, to obtain any reasonable yield of oil from the seed ifthe fin is not removed, and in my process the seeds are treated to remove the fin. This may be accomplished by milling in, for example a ball mill, or shaker mill, or the fins may be knocked'off by passing themthrough a-straight bladed centrifugal fan operating at high speeds. Likewise, any appreciable. water content in the seed will prevent satisfactory yields of oil during pressing. j} .51. 1 v I The seed, beforethe removal. of the fin, has the following approximate,composition: Protein, 33%; oil, 21%; ash, 3.'7%; Dextrin-like product, approximately 2%; andwax. constituents, 3 to 5%. After removal ofthe fins, which amount to 15 to 17% of thematuredseeds,;the protein content is increased to 39 to 40%;.theoil1and wax content to 28 to 30%, while the'ash and. other. constituents remain fairly constant. f

The step of removingthe fins isextremely important, as seeds with the fin attached have been subjected to pressures up to'30-40 tons per square inch without any appreciable amount of oil being obtained. Likewise, the natural water content of the seed must be reduced before any satisfactory yield of oil can-be obtained by pressing. Seed pressed while containing its. natural moisture content, about 8%, yielded no oil when subjected to pressures of the magnitude of those men- The moisture content should be reduced to below the maximum of about 8%, and preferably between 2 and 5%. When the fin has been removed and the moisture content is below the maximum set forth above; oil yields range from 16-25% byweight of thedefinned seed.

For the pressing operation the seed is ground to a small size, preferably 30-40 mesh, preferably on a differential s peed rollenmill. At particle sizes outside this range, it has been found that lower yields of oil are obtained.

The following examples will serve the various steps of the invention:

FIN Rnivioviu'. Example! In this example the seeds were definned by tumbling with shot. gms. of seed and 100 gms. of steel air rifle shot were tumbled for two m nutes with a back and forth motion at the rate to illustrate of about 100 strokes per minute. The product was separated by screening through a 14 mesh screen and the shot were removed magnetically. The two-minute tumbling treatment removed about 13 /:2% of the original weight of the seed as fins. Another run with a three-minute turn bling treatment removed 14% of the weight of the whole seed as fins.

Example H Two hundred (200) gms. seed and i560 lead V buckshot, average weight sagas. were tum" bled by a similar procedure'for 3 mifiu'tes. The product was passed through a 4 mesh screen to remove the shot after which the product was passed through a 14 mesh screen to removefins'; This treatment resulted in the removal of about 15% of the weight of the original see'd as fins. The apparent densitiesof the seed before and after tumbling were 0.252 and 0.495 respectively. E xafitzile fl? Three hundred (300) gins-.- of seedwere passed through a centrifugalfair, inthis instance an ordinary vacuum cleaner, and were then discharged into a cyclone separator of appropriate size. The seeds were removed has the bottom of thesepar'ator and the fins were eahausted through the top Withth air}- pro'cdure resiilted in the removal of about 16% of the original weight of the seed- By repeating this operationon the same Seeds; an add-itinal re= moval of about 1% obtained.

Fifty (50) gmsor qefinnd seedwere tone-a in water drained and dried w constantweightat 1109' o. The seed wa then gro nd by; passingitthrough rolls operati'ii'gfat diifereiitial speeds'. The seeds were passed through the rolls four times, at whiclitinie their Wie reduced to from 40-60 mesh. particle size is only approx'i mate as the oiliness of the seed prevented a more accurate determination of tii fiairticle size The round seed then repe ted to about 100- 1 C. and then pressed at iiflllfl lbs. per square inch for about 6 m nutes. gover or the weight of the seed was obtained as oil. Itwas bright in color like first pressing olive oil, and wasa'n excellent salad oil. The step of Heating the seed before pressing is believed to be i 'esiioj s'ibl for the pleas a t nutty savor of the on. The raw seed on the other hand had a characteristic bitter taste.

Example V Fifty (505 gm. of seed nth welsh the has been removed,- as in marine 1H. were dried and groiind and the seed, subjected to between -6 tons per s duare iricli pressure for" 19 hours during which time the teni bratiire' was normal room temperattir'e (approiiirnatly 1'8" Approiimately 1O (26%)" of ollof light yellow (greenish cast) 6016f resembling olivoil was ob'-' tained. It was mild tasting and made a good salad oil. 50 gni's; of defi-rind and similarly ground seed in'al were placed a pressure bylin der and the cylifidi, containing the charge of seed, was placed in an oven and heated to 105 C.

for two hours after which pressure was applied while the seed and pressing cylinder were still hot. At about 1000 lbs. per square inchpressiirejoil began to flow and continued for about six minutes when the pressure had reached about 6 tons per square inch. Approximately 12. 32 gins; (24.6%)

of oil was obtained by this hot-pressing procedure. The oil so obtained contained some of the natural Waxes of the seed, which appeared to be soluble in the hot oil and were hence removed along with the oil. The final cake weighed about 37.7 gms. andwas hard, dense and had the appearance of pressed wood. It had an apparent specific gravity of 1.32 and was capable of taking a high polish.

The characteristics of the oil depend somewhat onthe; conditions during harvesting and storage. In general the oilprepared from freshly cut but mature plants is fcun'd to be lighter in color and milder in flavor than the oil secured from plants allowed to ripen to the open pod stage in the field. The first mentioned oil will hereinafter be referred to as number 1 oil while the latter will be referred to as number 2 oil. The younger seed produces a much lighter and milder oil than that obtained from the fully ripened seed. It has also been found that the quantity of oil diminishes with the storage tirheo'f the seed. Whefe upwards of 20% of oil can be obtained from fresh seed, the amount" obtainable after a con-- siderable storage period usually is less than 20% and indeed after one year was found to be as low as 17%.

Physical characteristics of milkweed seed oil No; 1 Oil No. 2 Oil U Lightstraw, viz.slight Slightly darker't'haii reenish cast, l-ke No.1. dist pressing olive o Specific gravity 0.912 0.912. Refractwe index 1.47. 1.47. No l,- i a e 6 .7. Iodinenumber 116-125. Ac'et'yl niimbr- 222%}856 av apoiiificatidnmimer. Distillables, below 30% remainder poly- 30% remainder p'oly- 200 0. 14 mm. merized. merized. 'Hg pressure.

By" careful control of the distillation, keepin the heating time to a minimum, a residue can be obtained which, while being partially polymerized, is still soluble in conventional thinner or solvent. From this partially polymerized oil with the use of a suitable drier such as a lead and cobalt drier, a hard film can be produced in 15-24 hours drying tiine at room temperature, or about 15 hours at C. or in about 10 minutes" with an infra red drying lamp. The film formed is flexible, tough and practically impervious to water.

A tough, water-impervious film can be formed on surfaces using the raw oil and drying with an infra-red lamp. The surfaces must be such as to withstand the heat generated. A dry film will form in 10 to 12 minutes on some surfaces or the raw oil will set to a dry film in 2 or 3 weeks when exposed to the air under normal room temperaures.

While various modifications of the invention have been described iii detail. it is to be understood that the same is not limited thereto but may be varied within the scope of the appended claims.

What I claim isf V I 1. Process of preparing oil from milkweed seed which comprises removing the fin from the seed, and then subjecting the seeds to pressure while at a moisture content not substantially in excess of V 2. Process of preparing oil from milkweed seed which comprises mechanically removing the fins from the seed, and then subjecting the seeds to pressure while at a moisture content not substantially in excess of 8%.

3. Process of preparing oil from milkweed seed which comprises subjecting seed to impact to remove fins therefrom, separating the fins from the seed and then pressing the oil from the seed at a moisture content not substantially in excess of 8%.

4. Process of preparing oil from milkweed seed which comprises subjecting the seed to impact by tumbling to remove fins therefrom and then pressing oil from the seed at a moisture content not substantially in excess of 8%.

5. Process of preparing oil from milkweed seed which comprises collecting seed from freshly cut but mature plants, mechanically removing the fins from the seeds and then pressing the seeds at a moisture content not substantially in excess of 8%.

6. Process of preparing oil from milkweed seed which comprises removing the fin from the seed, and then subjecting the seeds to pressure while at a moisture content not substantially in excess of 2-5%.

7. Process of preparing oil from milkweed seed which comprises removing the fin from the seed, and then removing the oil from the seed while at REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 66,089 Ingersoll June 25, 1867 307,124 Leder Oct. 28, 1884 1,707,360 McFarland Apr. 2, 1929 2,015,242 Stadt Sept. 24, 1935 OTHER REFERENCES Chemical Abstracts 7887 (3). 

